In recent years, use of a three-dimensional printer that shapes a three-dimensional object having a three-dimensional shape has started increasing in various applications. In such a three-dimensional printer, the three-dimensional object can be shaped by layering a shaping material such as a discharged ink. For example, a color three-dimensional model forming device described in Japanese Unexamined Patent Publication No. 2001-18297 sectionalizes three-dimensional data configured by shape data for specifying a shape of a three-dimensional object and surface image data indicating an image of a surface to a plurality of layers, performs a halftone process (error diffusion, FM screening, AM screening) on the surface image data of each layer, and specifies the color of each pixel of the surface image data of each layer. The shaping material of a specified color is discharged from a discharging portion in order from a lowermost layer, and then cured and layered to shape a three-dimensional object complying with the three-dimensional data. This type of three-dimensional printer includes, for example, an inkjet type discharging portion for each color to discharge the ink serving as the shaping material such as yellow, magenta, cyan, black, and clear.